Visual Disturbances to Avatar Foot Position Increase Step-Width Variability in Immersive VR Treadmill Walking

Area of Science:

• Neuroscience
• Biomechanics
• Human-Computer Interaction

Background:

• Gait variability is essential for motor adaptation and learning.
• Current methods to increase gait variability often use force perturbations, which can decrease user motivation.
• Virtual reality (VR) offers a potential platform for novel gait perturbation methods.

Purpose of the Study:

• To investigate if subtle visual feedback distortion (VFD) in VR can increase gait variability.
• To assess if VFD impacts user motivation, embodiment, or simulator sickness.
• To explore the underlying mechanisms of VFD-induced gait changes.

Main Methods:

• Twenty healthy adults performed a stepping task on a treadmill in an immersive VR environment.
• Participants were exposed to a subtle, noise-like VFD of their avatar's foot position.
• Gait variability (step width and length) was measured, alongside self-report questionnaires.

Main Results:

• VFD significantly increased step width variability by approximately 15%, indicating enhanced lateral adaptability.
• Step length variability did not change significantly.
• Participants exhibited compensatory foot placement adjustments, suggesting proprioceptive recalibration.
• No significant changes were observed in embodiment, motivation, or simulator sickness.

Conclusions:

• Subtle VFD in VR is an effective, non-invasive method to increase gait variability, specifically step width variability.
• This approach enhances adaptability without negatively impacting user experience or motivation.
• VFD shows promise for promoting healthy gait dynamics and may be applicable in rehabilitation settings.